Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
J Neurosci Methods. 2010 Nov 30;193(2):217-25. doi: 10.1016/j.jneumeth.2010.08.019. Epub 2010 Sep 15.
The level of tissue oxygenation provides information related to the balance between oxygen delivery, oxygen utilization, tissue reactivity and morphology during physiological conditions. Tissue partial pressure of oxygen (PtO(2)) is influenced by the use of anesthesia or restraint. These factors may impact the absolute level of PtO(2). In this study we present a novel fiber optic method to measure brain PtO(2). This method can be used in unanesthetized, unrestrained animals, provides absolute values for PO(2), has a stable calibration, does not consume oxygen and is MRI compatible. Brain PtO(2) was studied during acute hypoxia, as well as before and after 28 days of high altitude acclimatization. A sensor was chronically implanted in the frontal cortex of eight Wistar rats. It is comprised of a fiber optic probe with a tip containing material that fluoresces with an oxygen dependent lifetime. Brain PtO(2) declines by 80% and 76% pre- and post-acclimatization, respectively, when the fraction of inspired oxygen declines from 0.21 to 0.08. In addition, a linear relationship between brain PtO(2) and inspired O(2) levels was demonstrated r(2)=0.98 and r(2)=0.99 (pre- and post-acclimatization). Hypoxia acclimatization resulted in an increase in the overall brain PtO(2) by approximately 35%. This paper demonstrates the use of a novel chronically implanted fiber optic based sensor for measuring absolute PtO(2). It shows a very strong linear relationship in awake animals between inspired O(2) and tissue O(2), and shows that there is a proportional increase in PtO(2) over a range of inspired values after exposure to chronic hypoxia.
组织氧合水平提供了与生理条件下氧输送、氧利用、组织反应性和形态之间平衡相关的信息。组织氧分压 (PtO2) 受麻醉或束缚的影响。这些因素可能会影响 PtO2 的绝对水平。在这项研究中，我们提出了一种测量脑 PtO2 的新型光纤方法。该方法可用于未麻醉、未束缚的动物，提供 PO2 的绝对值，具有稳定的校准，不消耗氧气，并且与 MRI 兼容。研究了急性低氧期间、高原适应前和适应后 28 天的脑 PtO2。传感器被慢性植入 8 只 Wistar 大鼠的额皮质。它由一个光纤探头组成，探头的尖端含有随氧依赖性寿命荧光的材料。当吸入氧分数从 0.21 下降到 0.08 时，脑 PtO2 分别下降 80%和 76%。此外，还证明了脑 PtO2 与吸入 O2 水平之间存在线性关系 r(2)=0.98 和 r(2)=0.99（适应前和适应后）。低氧适应导致整体脑 PtO2 增加约 35%。本文展示了一种新型慢性植入光纤传感器用于测量绝对 PtO2。它在清醒动物中显示出在吸入 O2 和组织 O2 之间非常强的线性关系，并表明在暴露于慢性低氧后，在一系列吸入值范围内，PtO2 呈比例增加。
